JPH0662908A - Method of manufacturing embossed sheet - Google Patents

Abstract

(57) [Summary] [Construction] The present invention relates to a method for producing an embossed sheet which is easy to make a plate mold and has good workability. The nonwoven fabric is laid on one magnetic material, and another magnetic material is further laid on it. Place a stencil equipped with a body, and bring the stencil into close contact with the non-woven fabric by the magnetic attraction of the one magnetic body and the other magnetic body, in this state pour the polyurethane elastomer into the stencil, squeegee, then heat It is characterized by hardening. [Effect] In the present invention, since the stencil 7 is brought into close contact with the non-woven fabric 9 by the magnetic attraction, the ON / OFF control can be performed very easily, and the attraction force can be uniformly applied to the entire surface. Since the strong and uniform suction action prevents bleeding of the polyurethane elastomer into the nonwoven fabric, a stencil can be applied. Further, this makes it possible to perform vacuum defoaming, and prevent defects such as bubble traces from occurring in the emboss. Furthermore, the depth of the hole 7a can be changed to manufacture embossings having various wall thicknesses.

Description

Detailed Description of the Invention

[0001]

[Object of the Invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sheet having anti-slip projections such as soles of sports shoes.

[0002]

BACKGROUND OF THE INVENTION In marathon shoes and jogging shoes, in order to reduce the weight of the shoes and to pursue shock absorption, the bottom of the ground contact surface is made of solid rubber or high-density sponge, and EVA (lightweight and excellent in cushioning) is formed on top of it. In recent years, a so-called multi-layered shoe sole, in which one or more sponges such as ethylene vinyl acetate) are laminated, has appeared. However, in these shoes, solid rubber with high hardness and high-density sponge are used in order to improve the ground gripping force and wear resistance due to the non-slip protrusions on the bottom of the ground contact surface, which inevitably leads to weight reduction of shoes. There was a limit.

Therefore, there is a method in which a polyurethane resin film on a non-woven fabric sheet and a liquid polyurethane composition before being made into non-slip projections are heat-cured by a mold to integrally bond them.
Japanese Patent Application No. 63-140729 (JP-A-1-310601)
No. gazette). According to this method, the shoe sole can be made as thin as possible and the entire shoe can be made lighter within a range in which the anti-slip projections are worn out early and lose the slip resistance.

Separately from this, the present inventors applied screen printing to print an appropriate embossed pattern on a non-woven fabric sheet made of thermoplastic resin fibers using ink made of a thermosetting resin. Then, with the embossed pattern corresponding to the recesses formed in one of the upper and lower molds, the non-woven sheet is sandwiched between the upper and lower molds, and this is heated and pressed to cure the ink forming the embossed pattern. In addition, a non-woven fabric sheet sandwiched between the flat portions of a pair of molds is formed into a solid film, and a method for producing an embossed sheet has already been developed.

However, with the former method, it is difficult to form a mold having a recess, and since the mold is used for a long period of time during the process, a large amount of mold is required. In addition, when filling the mold with the liquid polyurethane compound, it is necessary to remove the excess polyurethane compound called a squeegee, but if this process is not done carefully, the insufficiently removed part will become a handle. There is a problem that comes out.

Further, if the surface of the mold is scratched, the polyurethane compound in the scratch will be hardened to form a pattern, so that the mold must be handled carefully. Furthermore, in this method, since the polyurethane compound is heated and cured by covering it with a non-woven sheet from the top of the mold, defoaming of the polyurethane compound is difficult to occur, and a serious defect that a defect of a bubble mark is often generated in the emboss has a serious drawback. is there.

On the other hand, in the latter method, it is difficult to form a thick emboss. In recent sports shoes, the color contrast between the embossed part and the non-embossed part tends to give a colored design to the sole, but the latter method forms embossed rubber on the film. Therefore, the contrast as a material between the film and rubber cannot be clearly obtained.

[0008]

[Technical Items Attempted to Develop] The present invention has been made in view of such a background, and is premised on the use of the raw material in the former method so that the shoe sole can be colored. , An attempt was made to develop a method for manufacturing an embossed sheet that is easy to make a plate mold and has good workability.

[0009]

[Constitution of the invention]

[Means for Achieving the Object] That is, the method for producing an embossed sheet according to the first invention of the present application is to lay a base sheet on one magnetic body, and further place a stencil having another magnetic body thereon.
It is characterized in that the stencil is brought into close contact with the base sheet by a magnetic attraction action of the one magnetic body and the other magnetic body, and in this state, a polyurethane elastomer is poured into the stencil and then cured by heating.

The method for producing an embossed sheet according to the second invention of the present application is characterized in that, in addition to the above requirements, a thickener is mixed into the polyurethane elastomer. The above objects are intended to be achieved by these inventions.

[0011]

In the present invention, since a stencil is applied, it is easy to make a plate mold. Further, since the stencil and the base sheet are brought into close contact with each other by the action of attracting a magnetic force, the polyurethane elastomer does not ooze out from the boundary between the stencil and the base sheet to the surroundings, and it can be heated as it is. Further, by mixing a thickener into the polyurethane elastomer, the viscosity increases, which contributes to preventing the polyurethane elastomer from bleeding out, enables thick embossing, and enables early demolding.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings by taking the embossing of the sole 2 of an athletic shoe 1 as an example. Since the present invention forms an embossed pattern using a stencil, some methods of manufacturing the stencil will be described first.

I) Preparation of stencil a) Method of using master mold As shown in FIG. 2 (a), a master mold 3 having the same shape as the embossed shape of the shoe sole 2 is prepared, and iron, nickel or the like is added to the master mold 3. The magnetic metal 4 is sprayed. Then, the mold resin 6 is poured between the respective embossing molds 5 of the master mold 3 to be heat-cured,
As shown in FIG. 2B, the surface is ground to remove the magnetic metal 4 attached to the top surface of the embossing die 5 of the master die 3. Finally, by removing the master mold 3, a stencil 7 having a hole 7a as shown in FIG. 2 (c) is obtained. In the stencil 7 as described above, the magnetic metal 4 is provided on the lower surface other than the holes 7a, and this is for adhering the stencil 7 to the base sheet by magnetic force as described later.

As a similar technique for imparting magnetism to the stencil 7 in such a method, a method of supporting magnetic powder on the stencil 7 can be adopted. As a concrete method thereof, when the molding resin 6 is in a liquid state, magnetic powder is mixed into the liquid and poured into the master mold 3 to manufacture the stencil 7, or a stencil having no magnetism is used afterwards. The method of attaching can be adopted. Incidentally, the magnetic powder can be easily attached by a method of spraying the magnetic material into fine droplets with a gas flame, an arc flame, plasma or the like and spraying the magnetic material onto the stencil. In this method, the magnetic powder may adhere to the holes of the stencil, which may make it difficult to remove the plate. Therefore, it is necessary to use a mask or the like to prevent the magnetic substance from adhering to the holes. .

(B) Method of using a photocurable resin film First, a photocurable resin film is dried and molded into a film having a thickness of 2 mm to form a photocurable resin film 20. This is a negative film that is hydrophilic and water-developable. As an example, a raw material is one in which a styrylpyridinium group is introduced as a photosensitive group into a polyvinyl acetate / polyvinyl alcohol emulsion. This photocurable resin film 20 before exposure
As shown in FIG. 3 (a), the lower surface is wetted with water and then adhered to the substrate 21 such as glass or aluminum plate, and the temperature is kept at about 70 ° C. for 5 minutes.
Dry for 10 minutes to integrate both. Then Fig. 3
As shown in (b) and (c), a mask 22 in which an embossed pattern of the shoe sole is formed on the photocurable resin film 20 before exposure.
And the ultra-high pressure mercury lamp broad hand (365 nm,
After exposure at 5.7 mW / cm ² ) for 10 to 15 minutes, the mask 2
2 is removed, and the unexposed portion 20a is removed in a hot water shower using a brush or the like.

Next, after drying at about 70 ° C. for about 30 minutes and peeling the film from the substrate 21, the magnetic metal 4 is sprayed to form holes 7a in the unexposed portion 20a as shown in FIG. Create the stencil 7. In addition, in order to make the stencil 7 magnetic, magnetic powder may be applied in the same manner as described above, and the photocurable resin may be a film or a liquid one, which is applied and dried. Furthermore, since the photo-curing property of the photo-curing resin largely depends on its transparency, the amount of magnetic powder added is adjusted in consideration of the balance with the magnetic attraction force within the range of transparency.
It is necessary to cure with an electron beam having a higher energy level.

Since a photo-curable resin that can be developed by water is water-soluble before curing and rich in hydrophilicity even after curing, an embossed shoe sole (specifically, urethane elastomer) in which an oil-based raw material is often used. In consideration of the releasability with respect to, that is, the demolding property from the hole portion 7a of the stencil plate 7 having a thickness of several mm, it can be said to be a suitable type. What is water in water development?
It may be neutral or alkaline or acidic.

Further, as the photocurable resin, in addition to the above-mentioned photosensitive resins, natural water-soluble polymers such as carrageenan and gelatin, semi-synthetic water-soluble polymers such as carboxymethyl cellulose, ammonium alginate and starch methyl aminopropyl ether, and benzophenone and thioxanthone. , A benzoin ether or other photopolymerization initiator, and a photopolymerization type composed of a monomer, or a mixed type composed of a dichromate, a diazo resin, a photocrosslinking agent such as a bisazide compound. From the inside, it can be used in consideration of the compatibility and workability.

The "photo-curing" of the photo-curable resin used above absorbs energy and cross-links and cures when irradiated with high energy electromagnetic waves such as visible light, ultraviolet rays, X-rays and electron beams. The term “light” is a general term for electromagnetic waves with high energy.

C) Other methods In addition to the above methods, as shown in FIG. 4, an unexposed photo-curable resin film 20 and a magnetic plate 23 are bonded together, and an embossed pattern is provided on the photo-curable resin film 20 side. Mask 22
After closely contacting and exposing, a method of forming a stencil 7 by forming a hole 7a together with the magnetic plate 23 in a non-exposed portion by sand blasting using sand 24 or the like, or etching a metal plate, a resin plate or the like, laser, You may create a stencil by forming a hole part by methods, such as punching and a press. In this case,
When a magnetic material such as a resin plate is not used, the magnetic material may be embedded or bonded. Nowadays, according to the etching method, it is possible to form a stepped hole in a metal plate at a relatively low cost.

Next, the method of the present invention using the stencil 7 will be described step by step. ii) Set of stencil and base sheet First, as shown in FIGS. 5 and 6, a strong permanent magnet plate 8 is prepared, a non-woven fabric 9 as a base sheet is laid thereon, and the stencil 7 is placed thereon. As a result, the magnetic metal 4 of the stencil 7 is attracted to the permanent magnet plate 8 by a magnetic force, so that the nonwoven fabric 9 comes into close contact with the stencil 7.

As a method for adhering the non-woven fabric 9 and the stencil 7 to each other, it is conceivable to use a vacuum or a method of adhering. However, according to the vacuum, only the unmasked pores are sucked, and the elastomer is removed in this state. If it is poured, it will be sucked into the nonwoven fabric. Therefore, after all, it is difficult to suck the entire plate uniformly. Further, in the method using adhesive, it is necessary to apply the adhesive again each time. On the other hand, in the method using magnetic force, the disconnection of the suction action can be reliably controlled, the suction action can be exerted almost uniformly on the entire surface, and heating can be performed while maintaining the close contact between the nonwoven fabric 9 and the stencil 7. it can.

Although the permanent magnet plate 8 is applied in this embodiment, an electromagnet may be applied instead of the permanent magnet plate 8 and the stencil plate 7 is used.
Can be made of a magnetic material such as iron, or a permanent magnet can be embedded in the stencil 7. It is convenient for the magnet plate to take the form of an electromagnetic chuck that is widely used as a work holding device for a surface grinder, and it is preferable to set such a magnet plate instead of the permanent magnet plate.

The non-woven fabric 9 is a base for holding embossing, and may be made of either thermoplastic fiber or thermosetting fiber. One example thereof is a backskin artificial leather manufactured by Toray Industries, Inc. Exeine (registered trademark) or the like can be applied. Since there are various colors such as yellow and orange in this Exeine (registered trademark), the shoe sole can be given a design with a color contrast by making the embossing black. Besides this,
In addition to ordinary non-woven fabric sheets having tear strength, tensile strength, and abrasion resistance, a thick film sheet or the like can be applied to the base sheet. As a normal non-woven sheet, one obtained by self-bonding elastic long fibers such as urethane is suitable. still,
When the film sheet is used as the base fabric, it is difficult to express the contrast of the material in design as compared with artificial leather or non-woven fabric, but the color contrast can enhance the design.

Iii) Casting of polyurethane elastomer When the stencil 7 is set in close contact with the nonwoven fabric 9,
As shown in (a), the polyurethane elastomer 10 is poured into the holes 7a of the stencil 7. The pouring method of the polyurethane elastomer 10 is, as shown in FIG. 7 (a), a method of mixing two liquids of the raw material in a container, defoaming and pouring, a method of mixing the two liquids in a nozzle, As in 7 (a ′), the two liquids of the raw materials may be sprayed while being mixed at the tip of the nozzle.

The polyurethane elastomer 10 comprises a mixed solution of a prepolymer and polyisocyanate,
This is to be cured by heating, and in this example, Nipolan (registered trademark) of Nippon Polyurethane Industry Co., Ltd., which is a prepolymer, and Pandex (registered trademark) of Dainippon Ink and Chemicals, Inc., which is a polyisocyanate, are used. The mixture was used. The mixed solution of the prepolymer and polyisocyanate, which has been degassed in vacuum, is poured into the hole 7a. Further, as a polyurethane elastomer which is sprayed and supplied from a nozzle, there is a solventless quick-hardening urethane resin manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

Further, it is preferable to mix a thickener with these raw materials. That is, the above-mentioned two-component injection-type thermosetting polyurethane has a viscosity which once decreases as shown in FIG. 10 when it is heat-cured, and then increases. Therefore, at the viscosity decreasing point (point P in the figure), This is because it is necessary to prevent outflow from the stencil and bleeding into the nonwoven fabric.

A specific example of the thickener is AEROSIL (registered trademark) manufactured and sold by Nippon Aerosil Co., Ltd. This is the highest purity silica (S
iO ₂ 99.8%), is composed of ultrafine particles of 7 mμ to 50 mμ, and is a harmless substance having high surface area and high dispersibility. This AEROSIL (registered trademark) serves as a thickener because it can impart the rheological properties necessary for processing liquid substances such as polyester and epoxy resin with a small amount of addition due to the action of hydrogen cross-linking of silanol groups on the surface. It has the function of.

Incidentally, by adding a thickening agent and bringing the stencil 7 into close contact with the non-woven fabric 9 by magnetic force, the polyurethane elastomer 10 can be further prevented from oozing between the stencil 7 and the non-woven fabric 9, so that embossing The color boundary with the non-woven fabric becomes clear and the contrast becomes clear, so that the design effect of the shoe sole can be enhanced.

As another means for changing the color of the embossed portion to the color of the other non-woven fabric portion, the non-woven fabric portion to be embossed is preliminarily printed in a contrasting color, and the embossed portion is formed using a transparent resin. You may do it. In this case, on the embossed pattern printed with the ink of a contrasting color, a stencil having a hole formed at a position corresponding to the embossed pattern is brought into close contact, and a transparent polyurethane resin is poured into the hole and then heat-cured, The stencil may be separated.

Iv) Squeegee work: After the polyurethane elastomer 10 is poured into the hole 7a of the stencil 7, the squeegee tool 11 is used to protrude from the upper surface of the hole 7a as shown in FIG. 7 (b). To remove. Incidentally, the squeegee work here can be carried out very roughly because there is no defect that the pattern appears on the portion other than the embossment as in the invention of Japanese Patent Laid-Open No. 1-310601 mentioned above. However, since the squeegee surface is the top surface of the emboss, it is necessary to carefully perform the squeegee at that point, but the contrast of the pattern is slightly different due to the color difference between EXCENE (registered trademark) and the emboss. But not noticeable. Further, when an appropriate amount is poured into the hole 7a depending on the pattern of the hole 7a and the pouring of the polyurethane elastomer 10, it is possible to omit the squeegee work itself.

V) Heating and curing When the squeegee work is finished, as shown in FIG. 7 (c), the stencil 7, the nonwoven fabric 9 and the permanent magnet plate 8 are put in the oven 12 while being integrated, and heated at 120 ° C. for 45 minutes. The polyurethane elastomer 10 is cured, and in this state, FIG.
After removing the plate as shown in (a), 600 at 90 ° C. as shown in FIG. 8 (b) for the purpose of further stabilizing the elastomer.
By heating in an oven for a minute and then cooling this, FIG.
The shoe sole 2 having the desired embossment 13 is completed as shown in FIG.

When it is desired to provide a further step on the embossing 13, since the plate is not completely cured in the depressurized state shown in FIG. 8A, the embossed portion is directly pressed on the stencil by a die or the like. Alternatively, the embossing 13 can be provided with some steps by heat-pressing the embossing 13 using the metal mold 14 having the stepped concave portion 14a as shown in FIG. At this time, if the step is increased or the pressure is excessively applied, the entire emboss is flattened so as to buckle.

[0034]

According to the present invention, since the stencil 7 is brought into close contact with the nonwoven fabric 9 which is the base sheet by the magnetic attraction, the ON / OFF control can be performed very easily by using the electromagnet, and the attraction force can be applied to the entire surface. Can be applied uniformly. Further, such strong and uniform suction action prevents bleeding of the polyurethane elastomer into the nonwoven fabric, which leads to application of the stencil.

Further, since the stencil plate 7 can be used as described above, vacuum defoaming can be appropriately performed after the pouring of the polyurethane elastomer and the squeegee, and it is possible to prevent a defect of a bubble mark on the emboss. Furthermore, the depth of the holes 7a can be changed to make a wide range of thin embossing to thick embossing depending on the application, and the stencil 7 itself can be mass-produced at low cost. Furthermore, by mixing a thickener into the polyurethane elastomer 10, the stencil 7
There is also an advantage that the outflow from the fabric and the bleeding into the non-woven fabric are further strengthened and suppressed, and the plate can be removed at an early stage.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment in which a shoe sole manufactured by the method for manufacturing an embossed sheet of the present invention is applied to sports shoes.

FIG. 2 is a vertical cross-sectional view showing step by step the manufacturing process of a stencil used when carrying out the method for manufacturing an embossed sheet of the present invention.

FIG. 3 is a vertical cross-sectional view showing stepwise another manufacturing process of the same stencil.

FIG. 4 is a vertical cross-sectional view showing stepwise another manufacturing process of the same.

FIG. 5 is an exploded perspective view showing a laminated state of the stencil, the nonwoven fabric, and the permanent magnet.

FIG. 6 is a vertical sectional view of the same.

FIG. 7 is an explanatory view showing the method for producing an embossed sheet of the present invention step by step, which is a perspective view showing steps of pouring a polyurethane elastomer, squeegee work, and primary heating.

FIG. 8 is a perspective view showing each step of depressurization and secondary heating as well as the completed shoe sole.

FIG. 9 shows a molding method in which a step is formed on an emboss after plate removal,
It is a longitudinal cross-sectional view separately showing before and after molding.

FIG. 10 is a graph showing a change in viscosity when a two-component injection type thermosetting polyurethane is heat-cured.

[Explanation of symbols]

 1 Athletic Shoes 2 Sole 3 Master Type 4 Magnetic Metal 5 Embossing Type 6 Resin for 7 Mold 7 A Hole 8 Permanent Magnet Plate 9 Nonwoven Fabric 10 Polyurethane Elastomer 11 Squeegee Tool 12 Oven 13 Embossing 14 Mold 14a Recess 20 Light Curing Resin film 20a Unexposed part 21 Substrate 22 Mask 23 Magnetic plate 24 Sand P Viscosity decrease point

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Claims (2)

[Claims] 1. A base sheet is laid on one magnetic material, and a stencil having another magnetic material is placed on the base sheet, and the magnetic stencil is attracted by the one magnetic material and the other magnetic material. Is adhered to the base sheet, a polyurethane elastomer is poured into the stencil in this state, and then heat curing is carried out. 2. The method for producing an embossed sheet according to claim 1, wherein a thickener is mixed into the polyurethane elastomer.